1. Technical Field
The present invention relates to electromagnetic relays, and in particular, to a power load electromagnetic switch.
2. Related Art
Conventionally, in a power load electromagnetic switch, an electromagnetic repulsion acts between a fixed contact and a movable contact when an abnormal current flows in time of opening/closing of contact. The contact pressure thus lowers and the contact resistance becomes large thereby rapidly increasing the Joule heat or the contacts separate thereby generating an arc heat, whereby the movable contact and the fixed contact may be welded.
In order to prevent such welding of the contacts, there has been disclosed a movable contact supporting device of a switch in which a movable contact having an upper magnetic piece attached to an upper surface is arranged, so as to be slidable in the up and down direction by way of a pushing spring, in a window hole formed at a supporting board, and a lower magnetic piece is arranged, so as to be slidable in the up and down direction by way of a pushing spring, in a slide regulation hole formed at the lower side of the window hole with a wider than the width of the window hole so as to include a stopper at the upper part and the lower part (see Japanese Unexamined Utility Model Publication No. 60-163658).
More specifically, a movable contact 15 is sandwiched by two upper and lower magnetic pieces 13, 20, which are electromagnetic iron pieces, to resolve the drawback of electromagnetic repulsion, as shown in FIG. 4 of Japanese Unexamined Utility Model Publication No. 60-163658.